A) ANSWER THE FOLLOWING:
1) A triple bond is formed by the sharing of three electron between two atoms. Is this statement correct? If not, correct it.
2) Correct the following statements:
" The decomposition of molten sodium chloride by the action of electricity is an oxidation-reduction reaction in which sodium acts as an oxidizing agent and chlorine acts as a reducing agent".
3) What kind of compounds are soluble in water?
4) An atom has two electrones more than a noble gas configuration. What type of ion will it form ?
5) Which of the following compounds has the highest melting point?
C₃H₇OH , KCL or C₆H₅COOH
6) Why are atoms of metals and nonmetals reactive ?
7) a) Draw a diagram to show the formation of ammonium ion.
b) draw an electron dot diagram to illustrate the structure of a molecule of
I) nitrogen
ii) hydrogen chloride.
c) Hydronium ion label the lone pair of electrons.
8) Name the charged particles which attracts one another to form electrovalent compounds.
9) In the formation of electrovalent compounds, electrons are transferred from one element to another. How are electrons in the formation of a covalent compound?
10) The electronic configuration of nitrogen is 2, 5. How many electrons in outer shell of a nitrogen atom are not involved in the formation of a nitrogen molecule?
11) Elements A, B and C have atomic numbers 9, 20 and 10 respectively.
a) State which one is chemically inert.
b) Write down the formula of the compound formed by two of the above elements.
12) An element X has electronic configuration 2,8,18,8,1. Without identify X:
a) Predict the sign and charge on a simple ion of X.
b) write if X will an Oxidising agent or a reducing agent and why ?
13) a) Name two compounds, which are covalent, but on dissolving in water Conduct electicity.
b) Write one Property of any of the above compounds, which agrees with its being a covalent compound.
14) The hydrogen atom has only one valence electron. The carbon atom is 4 valence electrons. With the help of dot diagrams write down electronic configuration of elements in:
a) methane (CH₄)
b) ethylene (C₂H₄).
15) In the formation of compound XY₂, atom X gives one electron to each Y atom.
a) What is the nature of bond in XY₂
b) Give two Properties of XY₂.
16) An atom of fluorine may be written as ¹⁹₉F. Using electron dot diagram. Show electrons in outermost shell. Show how a molecule of fluorine (F₂) is formed. What is the name given to this kind of bonding?
17) Ionic compounds do not conduct electricity in the solid state. why ?
18) Explain:
a) Why is sodium ion (Na⁺) not reactive, but sodium metal is very reactive ?
b) Why hydrogen ion is called a proton ?
c) Why do covalent compounds have low melting and boiling points?
d) Why are ionic solids hard and brittle.
e) Why ionic solids are soluble in polar solvents.
f) Why compounds have high melting and boiling points.
g) Why covalent compounds do not allow the passage of electricity through them.
19) What kind of elements form positively charged ions ? Give two examples.
20) Define:
a) Electrovalency
b) Covalency
21) What are polar compounds? Give two examples.
22) Draw an electron dot diagram to illustrate the structure of a molecule of :
a) Nitrogen
b) hydrogen chloride.
23) a) Element Q and S react together to form an ionic compound. Under normal conditions . Which physical state will the compound QS exist in ?
b) Can Q and S both be metals ? Justify your answer.
24) In the formation of magnesium chloride (by direct combination between magnesium and chlorine), name the substan that is oxidised and the substance that is reduced.
25) Five atoms are labelled A to E as follows:
Atoms Mass no. Atomic no
A 40 20
B 19 9
C 7 3
D 16 8
E 14 7
a) which one of these atoms:
i) contains 7 protons?
ii) has an electronic configuration 2,7 ?
b) Write down the formula of the Compound formed between C and D.
c) Express these atoms as metals and non-metal.
26) An atom X has 2, 8, 7 electrons in its orbits. It combines with an another atom Y having 1 electron in its outermost orbit.
a) What type of bond will be formed between X and Y ?
b) Write the formula of the Compound formed.
c) Is it soluble in water or not ?
27) Elements X, Y and Z have atomic numbers 6, 9, and 12 respectively.
a) Which one forms:
I) an anion ii) a cation ?
b) Which has four electrons in the valence shell ?
28) What type of a bond is formed when the atoms have :
a) zero difference of electronegativity.
b) little difference of electronegativity.
c) high difference of electronegativity.
29) What type of chemical bonds are involved in the formation of the following compounds ?
a) NaCl.
b) HCl.
c) CHCl₃.
30) In the following reaction/
Cu²⁺ + Zn --> Cu + Zn²⁺
Name
a) the oxidizing agent.
b) the substance oxidized.
c) the substance gaining electrons.
31) Why do certain atoms form ions?
32) a) What are covalent compounds ?
b) How are these formed?
33) a) What are ionic compounds ?
b) How are these formed?
34) A hydrogen chloride molecule is called a polar covalent molecule. Give reason.
OR
Account for the ionic character in a covalent bond formed between H and CL.
35) What is a lone pair ? Give two examples to explain it.
36) What type of chemical bond is present in a carbon tetrachloride molecule (CCL₄).
37) copy and complete the following table:
Sodium Phosphorus
a) formula of chloride
b) physical state of chloride at room temperature (i.e., solid, liquid or gas)
c) Nature of bonding in chloride(i.e., ionic covalent)
38) Compound X consists of molecules.
Choose the correct answer
A) The type of bonding in X will be:
a) ionic b) electrovalent c) covalent d) molecules.
B) X is likely to have a:
a) low melting point and high boiling point.
b) high melting point and low boiling point.
c) low melting point and low boiling point.
d) high melting point and high boiling point.
C) In the liquid state, X will:
a) become ionic b) be an electrolyte c) conduct electricity d) not conduct electricity.
39) Identify the following reactions as either oxidation or reduction:
A) O + 2e⁻ --> O²⁻
B) K - e⁻ ---> K⁺ .
C) Fe³⁺ + e⁻ --> Fe²⁺.
40) Give the electron dot representation of the following molecules:
A) MgF₂ B) NaCl C) Cl₂ D) CH₄
41) Match the atomic numbers 4, 14, 8, 15 and 19 with each of the following:
a) A solid non-metal of valency 3.
b) A gas of valency 2.
c) A metal of valency 1.
d) A non-metal of valency 4.
42) The electronic configuration of atoms of three elements A, B and C are (2,8,1),(2,8,6) and (2,8,18,7) respectively.
a) Write down the formula of the molecule of B and its electron dot diagram. Mention the type of bonding.
b) write down the formula of the compound formed between A and C and type of bonding.
c) Classify the elements A, B and C as metals and non-metals.
d) Which element is likely to be a good conductor of electricity and why?
43) Some informations about elements D, E,F, G and H are given below:
Element At w At. N. Electron
D 9 4 2,2
E 19 9 2,7
F 23 11 2, 8,1
G 31 15 2,8,5
H 40 18 2,8,8
a) Will the compound found by E and F have ionic or molecule structure ?
b) Give the structure electron dot diagram of molecules E₂ between E and F.
c) which two elements can form ions with electronic configuration of noble gas in neon (atomic number 10)? Explain .
d) Which elements can be unreactive ?
44) An element C has the electronic configuration (2,8,18,8,1) without identifying C:
a) Predict the sign and charge on simple ion of C.
b) State whether you would expect the element C a metal or a non-metal.
c) Write the probable formula and appearance of chloride of C.
d) Write down the probable formula and solubility of hydroxide of C.
B) FILL THE BLANK:
1) Two chlorine atoms combine to form a molecule. The bond between them is....(ionic/covalent).
2) In forming O₂ molecule, ..... electrons are shared by each atom of oxygen.(two/three).
3) The number of single covalent bonds in a C₂H₂ molecules are....(two/one).
4) In forming N₂ molecule, ..... electrons are shared by each atom of nitrogen.(three/two).
5) Two atoms of the same element combine to form a molecule. The bond between them is known as...(ionic/covalent).
6) Methane is a ... compound.(covalent/Ionic).
7) CCL₄ is a..... compound.(covalent/ionic).
8) Halogens have a tendency to... electron readily.(lose/gain).
9) .....is a process by which electrons are apparently removed from an atom or an ion.(oxidation/reduction).
10) An oxidising agent is .....of electrons.(an accepter/ a donor).
11) .... compounds are undergo reactions.(electrovalent/covalent).
12) A ..... bond is a pair of electrons shared by two atoms.(ionic/covalent).
13) The bond in the hydrogen molecule is called a......bond.(single/double).
14) A covalent bond that is shared equally between two bounded. atoms is called a .... covalent bond. (Polar/non-polar).
15) The ability of an atom to attract shared electrons is called it's ....(electropositively/electronegativity).
C) NAME THE FOLLOWING :
1) One bivalent anions and one trivalent cation.
2) Two cations isoelectronic to neon.
3) Two anions isoelectronic to argon.
4) Two ionic compounds.
5) Two covalent compounds.
6) The compound formed by either gaining or losing electrons.
7) The compound formed by sharing of electrons.
8) Oxidising agent in the Equation: 2MG + O₂ ---> 2MGO.
9) CuO + H₂ --> Cu + H₂O.
10) The bond formed in a molecule of N₂.
11) One electrovalent compound containing chlorine.
12) One covalent compound containing chlorine.
13) Two compounds which contain both ionic and covalent bonds.
14) The bond formed between two or more non-metals.
D) TRUE OR FALSE:
1) Ionic compounds are soft solids or liquids at ordinary temperature.
2) Carbon dioxide is an electrovalent compound.
3) Ionic bond involves sharing of electrons.
4) Covalent bond involves transference of electrons.
5) KCL is an iconic compound.
6) The shape of a methane molecule is tetrahedral.
7) Covalent compounds are generally gaseous due to the presence of weak electrostatic forces of attraction.
8) Covalent compounds are usually insoluble in water but are soluble in organic solvents.
9) A compound made up of two or more non-metal is an equivalent compound.
10) The bond formed between the atoms of the same element is an iconic bond.
E) REASON BEHIND:
1) Ionic compounds do not conduct electicity in the solid state. Why ?
2) Why is sodium ion (Na+) not reactive, but sodium metal is very reactive ?
3) Why hydrogen ion is called a proton ?
4) Why do covalent compounds have low melting and boiling points.
5) Why are ionic solids hard and brittle ?
6) Ionic solids are soluble in polar solvents.
7) Ionic compounds have high melting and boiling points.
8) Covalent compounds do not allow the passage of electicity through them.
9) Why is a methane molecule called a non-polar compound.
F) DEFINE:
1) Electrovalency
2) Covalency
3) Polar compounds
4) Covalent compounds
5) Ionic compounds
6) Lone pair
G) DIFFERENCE BETWEEN
1) Ionic compound / Polar covalent compound
2) Polar covalent compound/ Non-polar covalent compound.
3) a) sodium atom/sodium ion
b) chlorine atom/ chlorine ion.
with respect to:
i) atomic structure
ii) electrical state
iii) chemical action
iv) toxicity
4) Ionic compounds/covalent compounds.
H) CHOOSE THE CORRECT Answer:
1) which of the following is not soluble in water?
A) NaCl B) KBr.
C) CaCl₂ d) CH₃Cl
2) When two pairs of electrons are shared, the bound formed between the atom is:
A) single covalent bond
B) double covalent bond
C) single ionic bond
D) triple covalent bond.
3) Which of the following is not a covalent molecule?
A) CHCl₃ b) NaCl c) CH₄ d) SO₂
4) Formation of an ionic compound is favoured by:
A) low ionization potential of the cation.
B) high ionization potential of the cation
C) low electron affinity of the anion.
D) low charge on the cation and the anion.
5) Hydrogen molecule is:
A) nonpolar. B) ionic
C) covalent. D) polar
6) polar compound are:
A) soluble in water
B) insoluble in water
C) soluble in organic solvents
D) soluble in none.
7) A polar covalent bond is formed by:
A) the transference of one electron
B) the transference of one or more electrons.
C) no sharing of electrons
D) sharing of one or more electrons.
8) Covalent compounds:
A) are generally insoluble in water.
B) have high melting points
C) conduct electricity in their aqueous solutions
D) are generally solids
9) Which of the following statements regarding a covalent bond is not true?
A) The electrons are shared between atoms
B) The bond is non-directional
C) The strength of the bond depends upon the extent of electron affinity.
D) The bond formed may or may not be polar
10) In a double bond connecting two atoms, there is a sharing of:
A) 2 electrons. B) 4 electrons
C) 1 electron. D) all electrons
11) The property which is characteristic of an electrovalent compound is that:
A) it is easily vaporized
B) it has a high melting point
C) it is a weak electrolyte
D) it often exists as a liquid.
12) When a metal atom becomes an ion:
A) it loses electrons and is oxidised
B) it gains electrons and is reduced.
C) it gains electrons and is oxidised
D) it loses electrons and is reduced.
12) Identify the following reactions as either oxidation or reduction?
a) O + 2e⁻ ----> O²⁻
b) K - e ⁻ ---> K⁺
c) Fe³⁺ + e ⁻ ---> Fe²⁺
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